Pressing ‘1’ could make it costly call

Dear Sir — Just received a call from an automated female voice purporting to be from BT technical dept telling me that my IP address had been compromised and urging me to press “1” to be connected to receive advice.
I cut off the call and did a bit of digging and apparently it is very similar to the Microsoft scam, in that they want £400 off you in order to put things right and protect your PC.
For older people or those not tech savvy it could prove costly to make that call. — Yours faithfully,